I always wonder why these guides stick to x86(-64). I get that it's still the most popular processor architecture for desktop computing, but it's got a lot of complex legacy baggage that's an unnecessary cognitive burden for beginners. It's also a relatively uncommon target for real-world bare metal development. Why not target RISC-V? I've done a lot of OSDev in both x86 and RISC-V, and I think RISC-V is much more teachable. You don't want to bog the reader down trying to understand what protected mode, or the A20 line is, when you could just focus on more universal concepts.

In case anyone is curious, I very recently released a small demo kernel for RISC-V here: https://github.com/ajxs/straylight